Are you jesting? A judge can ban you from everyplace excepting a 5x8 concrete pad enclosed with iron bars (commonly referred to as a "cell").
In reallity, the Gov't rarely punishes non-violent acts of civil disobediance/protest with anything more than a fine and time served while awaiting trial (days to a few months). For history, look at all the anti-nuke demonstrators who regularly chain themselves to the fences at air force bases. The key here is non-violance. As long as nobody got hurt and there wasn't any real possibility of anybody getting hurt, they will give the guy a small to moderate fine.
If he is not close to retirement, he might get fired from the postal service.